Question

初二分式的数学题 急 +++++分的

已知x^2+x-1=0,求x(1-2/1-x)除以(x+1)-x(x^2-1)/x^2-2x+1的值. 急啊 要过程 可以+++++++分

Answer 1

x^2+x-1=0
x^2=1-x
x^2/(1-x)=1
x[1-2/(1-x)]÷(x+1)-x(x^2-1)/(x^2-2x+1)
=x[(x+1)/(x-1)]*1/(x+1)-x(x+1)/(x-1)
=x/(x-1)-x(x+1)/(x-1)
=[x-x(x+1)]/(x-1)
=[x-x^2-x]/(x-1)
=-x^2/(x-1)
=x^2/(1-x)
=1

Answer 2

式子难理解，能不能写清楚点

Answer 3

x([1-2/(1-x)]/(x+1)-x(x^2-1)/(x^2-2x+1)
=-x/(1-x)-x(x^2-1)/(x-1)^2
=x/(x-1)-x(x-1)(x+1)/(x-1)^2
=x/(x-1)-(x^2+x)/(x-1)
=-x^2/(x-1)=-（1-x)/(x-1)=1.

Answer 4

答案等于1，首先将这个式子的第一部分的分子分母同时乘以一个（1-x)，然后化简成为x/(x-1),
然后将第二部分的分子分母展开，x^2-1展开成(x+1)(x-1), x^2-2x+1展开成(x-1)^2,分子分母上下约分可得x(x+1)/(x-1)。